Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C17/00—Preparation of halogenated hydrocarbons
  • C07C17/25—Preparation of halogenated hydrocarbons by splitting-off hydrogen halides from halogenated hydrocarbons

Definitions

• This disclosure relates in general to methods of synthesis of fluorinated olefins and fluorinated alkynes.
• chlorofluorocarbons CFCs
• hydrochlorofluorocarbons HCFCs
• HFC hydrofluorocarbon
• These new compounds such as HFC refrigerants, HFC-134a and HFC-125, and blowing agents HFC-134a and 245fa being the most widely used at this time, have zero ozone depletion potential and thus are not affected by the current regulatory phase-out as a result of the Montreal Protocol.
• compositions that meet both low ozone depletion standards as well as having low global warming potentials.
• Certain hydrofluoroolefins are believed to meet both goals.
• manufacturing processes that provide halogenated hydrocarbons and fluoroolefins that contain no chlorine that also have a low global warming potential.
• Several hydrofluoroolefins have been identified which meet these goals.
• One such olefin is 1 ,1 ,1 ,4,4,4-hexafluoro-2-butene. Efficient methods of synthesis are needed for such compounds.
• the chlorinated reactant comprising, reacting a chlorinated reactantwith an aqueous solution of an alkali metal hydroxide in the presence of a phase transfer catalyst.
• the chlorinated reactant includes a chlororfluorobutane or a chlorofluorobutene. In one embodiment, the chlorinated reactant is
• HCFC-336mdd (2,3-dichloro-1 ,1 ,1 ,4,4,4-hexafluorobutane), HCFC- 336mfa (2,2-dichloro-1 ,1 ,1 ,4,4,4-hexafluorobutane) or HCFO-1326mxz (E- or Z- 1 ,1 ,1 ,4,4,4-hexafluoro-2-chloro-2-butene).
• HCFC-336 is meant to include either or both of the aforementioned HCFC- 336 isomers.
• the phase transfer catalyst is a quaternary alkylammonium salt.
• the quaternary alkylammonnium salt has at least one alkyl group of at least 8 carbons, and recovering the hexafluoro-2-butyne, wherein the conversion of dichloro-1 ,1 ,1 ,4,4,4-hexafluorobutane is at least 50% per hour.
• Also disclosed is a process for producing hexafluoro-2-butyne comprising, reacting a chlorinated reactant with an aqueous solution of an alkali metal hydroxide in the presence of a quaternary alkylammonium salt having alkyl groups of from four to ten carbon atoms, and mixtures thereof, and a non-ionic surfactant, and recovering the hexafluoro-2-butyne, and wherein the conversion of chlororinated reactant to hexafluoro-2-butyne is at least 20% per hour
• Also disclosed is a process for producing hexafluoro-2-butyne comprising, reacting a chlorinated reactant with an aqueous solution of an alkali metal hydroxide in the presence of a quaternary alkylammonium salt having alkyl groups of from four to ten carbon atoms, and mixtures thereof, and a non-ionic surfactant, and recovering the hexafluoro-2-butyne, and wherein the conversion of chlorinated reactant to hexafluoro-2-butyne is at least 20% per hour
• HCFC-336 without a designation of positional isomers, refers to either or both of HCFC-336mdd (2,3-dichloro- 1 ,1 ,1 ,4,4,4-hexafluorobutane) or HCFC-336mfa (2,2-dichloro-1 ,1 ,1 ,4,4,4- hexafluorobutane).
• HCFC-1326mxz without designation of stereochemistry refers to either or both of E- or Z- HCFC- 1326mxz (E-1 ,1 ,1 ,4,4,4-hexafluoro-2-chloro-2-butene or Z-1 ,1 ,1 ,4,4,4- hexafluoro-2-chloro-2-butene).
• HCFC-336 is potentially available through a number of routes, and is of interest as a potential precursor to 1 ,1 ,1 ,4,4,4-hexafluoro-2-butene.
• HCFC-336 could be prepared by hydrogenation of CFC-1316mxx, or via chlorination of HFC-356mff. Dehydrochlorination twice would provide hexafluoro-2-butyne, which could be readily hydrogenated to provide cis- 1 ,1 ,1 ,4,4,4-hexafluoro-2-butene.
• dehydrochlorination of vinyl chlorides is classical organic chemistry to form acetylenes requires rather harsh conditions, such as very strong bases such as sodium in liquid ammonia. It has been reported that higher molecular weight polyfluorinated vinyl chlorides can be dehydrohalogenated to alkynes using aqueous base at temperatures of from 100-120°C up to 200 or 250°C. At these
• HCFC-336mdd or HCFC-336mfa can be twice dehydrochlorinated at temperatures well below 100°C using an aqueous basic solution in combination with quaternary alkylammonium salts as a phase transfer catalyst.
• phase transfer catalyst is intended to mean a substance that facilitates the transfer of ionic compounds into an organic phase from an aqueous phase or from a solid phase.
• the phase transfer catalyst facilitates the reaction of these dissimilar and incompatible components. While various phase transfer catalysts may function in different ways, their mechanism of action is not determinative of their utility in the present invention provided that the phase transfer catalyst facilitates the dehydrochlorination reaction.
• phase transfer catalyst as used herein is a quaternary
• alkylammonium salt wherein the alkyl groups are alkyl chains having from four to ten carbon atoms.
• alkylammonium salt is trioctylmethylammonium chloride (Aliquat 336).
• the anions of the salt can be halides such as chloride or bromide, hydrogen sulfate, or any other commonly used anion.
• the quaternary alkylammonium salt is tetraoctylammonium chloride. In yet another embodiment, the quaternary alkylammonium salt is tetraoctylammonium hydrogen sulfate.
• phase transfer catalysts include crown ethers, cryptands or non-ionic surfactants alone, do not have a significant effect on conversion or the rate of the dehydrochlorination reaction in the same fashion.
• either HCFC-336mdd or HCFC-336mfa can be twice dehydrochlorinated at temperatures well below 100°C using an aqueous basic solution in combination with quaternary alkylammonium salts wherein the alkyl groups are alkyl chains of at least four or more carbon atoms and further in combination with a non-ionic surfactant.
• a quaternary alkylammonium salt is tetrabutylammonium chloride.
• the non-ionic surfactant is an ethoxylated nonylphenol or an ethoxylated C12-C15 linear aliphatic alcohol.
• Suitable non-ionic surfactants include Bio-soft® N25-9 and Makon® 10 are from Stepan Company.
• the quaternary alkylammonium salt is selected from the group consisting of tetrabutylammonium chloride,
• tetraoctylammonium hydrogen sulfate methytrioctylammonium chloride, methyltrioctylammonium bromide, tetradecylammonium chloride, tetradecylammonium bromide, and tetradodecylammonium chloride.
• Dehydrochlorination of HCFC-336 can be effected with quaternary alkylammonium salts, wherein the alkyl groups are alkyl chains having at least one alkyl chain of 8 carbons or more.
• the quaternary alkylammonium salt has three alkyl chains of 8 carbons or more, such as trioctylmethylammonium salt.
• the quaternary alkylammonium salt is a tetraoctylammonumium salt.
• the anions of the salt can be halides such as chloride or bromide, hydrogen sulfate, or any other commonly used anion.
• the quaternary alkylammonium salts is added in an amount of from 0.5 mole percent to 2.0 mole percent of the HCFC- 336. In another embodiment, the quaternary alkylammonium salts is added in an amount of from 1 mole percent to 2 mole percent of the HCFC-336. In yet another embodiment, the quaternary alkylammonium salts is added in an amount of from 1 mole percent to 1 .5 mole percent of the HCFC-336.
• the quaternary alkylammonium salt is added in an amount of from 1 mole percent to 1 .5 mole percent of the HCFC-336 and the weight of non-ionic surfactant added is from 1 .0 to 2.0 times the weight of the quaternary alkylammonium salt.
• the reaction is conducted at a temperature of from about 60 to 90°C. In another embodiment, the reaction is conducted at 70°C.
• the basic aqueous solution is a liquid (whether a solution, dispersion, emulsion, or suspension and the like) that is primarily an aqueous liquid having a pH of over 7. In some embodiments the basic aqueous solution has a pH of over 8. In some embodiments, the basic aqueous solution has a pH of over 10. In some embodiments, the basic aqueous solution has a pH of 10-13. In some embodiments, the basic aqueous solution contains small amounts of organic liquids which may be miscible or immiscible with water. In some embodiments, the liquid medium in the basic aqueous solution is at least 90% water. In one embodiment the water is tap water; in other embodiments the water is deionized or distilled.
• the base in the aqueous basic solution is selected from the group consisting of hydroxide, oxide, carbonate, or phosphate salts of alkali, alkaline earth metals and mixtures thereof.
• bases which may be used lithium hydroxide, sodium hydroxide, potassium hydroxide, calcium hydroxide, magnesium oxide, calcium oxide, sodium carbonate, potassium carbonate, sodium phosphate, potassium phosphate, or mixtures thereof.
• Hydrofluorochloroolefin HCFC-1326mxz is an impurity in some schemes for the synthesis of 1 ,1 ,1 ,4,4,4-hexafluoro-2-butene, which is of interest as a foam expansion agent. In other potential schemes, it can be an intermediate.
• One method of synthesis of HCFC-1326mxz is through the hydrogenation of 1 ,1 ,1 ,4,4,4-hexafluoro-2,3-dichloro-2-butene.
• Dehydrochlorination would provide hexafluoro-2-butyne, which could be hydrogenated to provide 1 ,1 ,1 ,4,4,4-hexafluoro-2-butene.
• dehydrochlorination of vinyl chlorides to form acetylenes requires rather harsh conditions, such as very strong bases, such as sodium in liquid ammonia. It has been reported that higher molecular weight polyfluorinated vinyl chlorides can be
• phase transfer catalyst is intended to mean a substance that facilitates the transfer of ionic compounds into an organic phase from an aqueous phase or from a solid phase.
• the phase transfer catalyst facilitates the reaction of these dissimilar and incompatible components. While various phase transfer catalysts may function in different ways, their mechanism of action is not determinative of their utility in the present invention provided that the phase transfer catalyst facilitates the dehydrochlorination reaction.
• phase transfer catalyst as used herein is a quaternary
• alkylammonium salt wherein the alkyl groups are alkyl chains having from four to twelve carbon atoms.
• the quaternary alkyl ammonium salt is a tetrabutylammonium salt.
• the anions of the salt can be halides such as chloride or bromide, hydrogen sulfate, or any other commonly used anion.
• the quaternary alkylammonium salt is trioctylmethylammonium chloride (Aliquat 336). In another embodiment, the quaternary alkylammonium salt is tetraoctylammonium chloride. In yet another embodiment, the quaternary alkylammonium salt is
• phase transfer catalysts include crown ethers, cryptands or non-ionic surfactants alone, do not have a significant effect on conversion or the rate of the dehydrochlorination reaction in the same fashion.
• the anions of the salt can be halides such as chloride or bromide, hydrogen sulfate, or any other commonly used anion.
• the quaternary alkyi ammonium salt is a tetrabutylammonium salt.
• the quaternary alkylammonium salt is a tetrahexylammonium salt.
• the quaternary alkylammonium salt is a tetraoctylammonumium salt.
• the quaternary alkylammonium salt is a trioctylmethylammonumium salt.
• Dehydrochlorination of the E-isomer of 1 ,1 ,1 ,4,4,4-hexafluoro-2- chloro-2-butene can be effected with quaternary alkylammonium salts, wherein the alkyi groups are alkyi chains having at least one alkyi chain of 8 carbons or more.
• the quaternary alkylammonium salts wherein the alkyi groups are alkyi chains having at least one alkyi chain of 8 carbons or more.
• alkylammonium salt has three alkyi chains of 8 carbons or more, such as trioctylmethylammonium salt.
• the quaternary alkylammonium salt is a tetraoctylammonumium salt.
• the quaternary ammonium salt is a tetradecylammonium salt.
• the quaternary alkylammonium salt is a tetradodecylammonium salt.
• the anions of the salt can be halides such as chloride or bromide, hydrogen sulfate, or any other commonly used anion.
• dehydrochlorination of the E-isomer of 1 ,1 ,1 ,4,4,4-hexafluoro-2-chloro-2-butene can be effected with quaternary alkylammonium salts, wherein the alkyi groups are alkyi chains having from four to twelve carbon atoms, and in the presence of a non-ionic surfactant.
• the non-ionic surfactants can be ethoxylated nonylphenols, and ethoxylated C12 to C15 linear aliphatic alcohols.
• Suitable non-ionic surfactants include Bio-soft® N25-9 and Makon® 10 are from Stepan Company.
• the quaternary alkylammonium salts is added in an amount of from 0.5 mole percent to 2.0 mole percent of the
• the quaternary alkylammonium salts is added in an amount of from 1 mole percent to 2 mole percent of the 1 ,1 ,1 ,4,4,4-hexafluoro-2-chloro-2-butene. In yet another embodiment, the quaternary alkylammonium salts is added in an amount of from 1 mole percent to 1 .5 mole percent of the 1 ,1 ,1 ,4,4,4- hexafluoro-2-chloro-2-butene.
• the dehydrochlorination of Z- or E- 1 ,1 ,1 ,4,4,4- hexafluoro-2-chloro-2-butene is conducted in the presence of an alkali metal halide salt.
• the alkali metal is sodium or potassium.
• the halide is chloride or bromide.
• the alkali metal halide salt is sodium chloride. Without wishing to be bound by any particular theory, it is believed that the alkali metal halide salt stabilizes the phase transfer catalyst.
• Addition of alkali metal halide salt also reduces the amount of fluoride ion measured in the water effluent from the reaction.
• the presence of fluoride is believed to result from decomposition of either the 1 ,1 , 1 ,4,4,4-hexafluoro- 2-chloro-2-butene starting material, or the hexafluoro-2-butyne product.
• the amount of fluoride ion found in the water effluent from the dehydrochlorination is about 6000 ppm. In several examples, using from 30 to 60 equivalents of sodium chloride per mole of phase transfer catalyst, the amount of fluoride ion in the water effluent is reduced to 2000 ppm. In one embodiment, the alkali metal halide is added at from 25 to 100 equivalents per mole of phase transfer catalyst. In another embodiment, the alkali metal halide is added at from 30 to 75 equivalents per mole of phase transfer catalyst. In yet another
• the alkali metal halide is added at from 40 to 60 equivalents per mole of phase transfer catalyst.
• the reaction is conducted at a temperature of from about 60 to 90°C. In another embodiment, the reaction is conducted at 70°C.
• the basic aqueous solution is a liquid (whether a solution, dispersion, emulsion, or suspension and the like) that is primarily an aqueous liquid having a pH of over 7. In some embodiments the basic aqueous solution has a pH of over 8. In some embodiments, the basic aqueous solution has a pH of over 10. In some embodiments, the basic aqueous solution has a pH of 10-13. In some embodiments, the basic aqueous solution contains small amounts of organic liquids which may be miscible or immiscible with water. In some embodiments, the liquid medium in the basic aqueous solution is at least 90% water. In one embodiment the water is tap water; in other embodiments the water is deionized or distilled.
• the base in the aqueous basic solution is selected from the group consisting of hydroxide, oxide, carbonate, or phosphate salts of alkali, alkaline earth metals and mixtures thereof.
• bases which may be used lithium hydroxide, sodium hydroxide, potassium hydroxide, calcium hydroxide, magnesium oxide, calcium oxide, sodium carbonate, potassium carbonate, sodium phosphate, potassium
• Tetra-n-butylammonium bromide (TBAB), Tetra-n- butylammonium hydrogen sulfate, Trioctylmethylammonium chloride
• TMAB Tributylmethylammonium bromide
• Bio-soft® N25-9 and Makon® 10 are from
• HCFC-336mfa is CF3CCI2CH2CF3
• HCFC-336mdd is CF3CHCICHCICF3
• HFB is CF 3 C ⁇ CCF 3
• Example 1 demonstrates the conversion of 336mdd to
• Example 2 demonstrates the conversion of 336mfa to hexafluoro-2- butyne in the presence of Aliquat 336.
• NaOH aqueous solution (22 ml_, 0.22 mol) is added to the 336mfa (23.5 g, 0.1 mol) and water (5.6 ml_) in the presence of Aliquat® 336 (0.53 g, 0.001325 mol) at room temperature.
• the reaction temperature is raised to 70 °C after the addition, and gas chromatography is used to monitor the reaction.
• the reaction is completed after 2 hour and the hexafluorobutyne is collected in a dry ice trap.
• Example 3 demonstrates the conversion of 336mfa to hexafluoro-2- butyne in the presence of tetrabutylammonium chloride and non-ionic surfactant.
• tetrabutylammonium bromide (0.45 g, 0.001325 mol) and Makon® 10 (0.7 g) at room temperature.
• the reaction temperature is raised to 70 °C after the addition, and gas chromatography is used to monitor the reaction.
• the reaction is completed after 4.5 hours and the hexafluorobutyne is collected in a dry ice trap.
• NaOH aqueous solution (23 ml_, 0.23 mol) is added to the mixture of HCFC-336mfa (23.5 g, 0.1 mol) and water (18 ml_) at 37 °C.
• the reaction temperature is raised to 70 °C after the addition, and gas chromatography was used to monitor the reaction. After thirty one hours. 0.36 g hexafluoro-2-butyne (conversion: 2.2%; yield: 2.2%) was collected in a dry ice trap.
• NaOH aqueous solution (10 mL, 0.10 mol) is added to the mixture of HCFC-336mfa (1 1 .8 g, 0.05 mol) and water (18 mL) at 37 °C in the presence of 15-Crown-5 (0.65 g, 0.003 mol).
• the reaction temperature is raised to 70 °C after the addition, and gas chromatography is used to monitor the reaction.
• the reaction is not completed after thirty hours. 1 .16 g hexafluoro-2-butyne (conversion: 14%; yield: 14%) is collected in a dry ice trap.

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• 2013
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